Plate and Frame Heat Exchangers with Variable Chamber Sizes

ABSTRACT

Devices, systems, and methods for a heat exchanger and operation of a heat exchanger are disclosed. The heat exchanger comprises a chamber with a plurality of fluid inlets and a plurality of fluid outlets. The chamber comprises plates, the plates being parallel and defining fluid plenums between each of the plates. The fluid plenums define a fluid flow path, wherein each of the fluid plenums are aligned with one of the plurality of fluid inlets, one of the plurality of fluid outlets, a fluid path between at least two of the fluid plenums, or a combination thereof. The plates are mounted on guides perpendicular to a plane of the plates. The plates move along the guides due to changes in pressure in the fluid plenums, application of an external force to the one or more plates, or a combination thereof.

GOVERNMENT INTEREST STATEMENT

This invention was made with government support under DE-FE0028697awarded by the Department of Energy. The government has certain rightsin the invention.

FIELD OF THE INVENTION

The devices, systems, and methods described herein relate generally toplate and frame heat exchange. More particularly, the devices, systems,and methods described herein relate to plate and frame exchangers withvariable chamber sizes.

BACKGROUND

Plate and frame heat exchangers are used in most industries as they arecompact and cheap to make. However, they are very inflexible inoperation, due to their rigidity and lack of moving parts. This preventsvarying of various flow parameters during operations inside theexchanger. A plate and frame heat exchanger that overcomes theselimitations is needed.

SUMMARY

Devices, systems, and methods for a heat exchanger and operation of aheat exchanger are disclosed. The heat exchanger comprises a chamberwith a plurality of fluid inlets and a plurality of fluid outlets. Thechamber comprises one or more plates, the one or more plates beingparallel and defining fluid plenums between each of the one or moreplates. The fluid plenums define a fluid flow path, wherein each of thefluid plenums are aligned with one of the plurality of fluid inlets, oneof the plurality of fluid outlets, a fluid path between at least two ofthe fluid plenums, or a combination thereof. The one or more plates aremounted on guides perpendicular to a plane of the one or more plates.The one or more plates move along the guides due to changes in pressurein the fluid plenums, application of an external force to the one ormore plates, or a combination thereof.

The heat exchanger may further comprise spacers that limit movement ofthe one or more plates. The spacers may be mounted on the guides. Thespacers may also be mounted on the one or more plates. The spacers mayalso limit the movement of the one or more plates such that the fluidplenums aligned with each of the plurality of fluid inlets and each ofthe plurality of fluid outlets do not change.

The one or more plates comprising the heat exchanger may also besufficiently rigid that the one or more plates moves when an even forceis applied to the plate.

The one or more plates may comprise silicone, aluminum, steel, copper,bronze, plastic, or combinations thereof. The one or more plates mayalso flex such that solids deposited on the one or more plates breakoff.

The one or more plates may also be pre-tensioned to buckle when apressure differential between sides of the one or more plates exceeds alimit. The one or more pre-tensioned plates flex such that solidsdeposited on the one or more plates break off.

The one or more plates may be prevented from moving when a temperaturelimit is reached by a mechanical locking mechanism, temperature-inducedexpansion or contraction of the one or more plates, temperature-inducedexpansion or contraction of the chamber, or combinations thereof.

The one or more plates comprise an electroactive material that flexes ordeforms when a charge is applied to the one or more plates.

The heat exchanger may further comprise one or more pressure sensors,one or more temperature sensors, or a combination thereof.

The one or more plates may be vibrated to break off solids deposited onthe one or more plates.

The external force applied to the one or more plates may be provided bya piston, gears, electromagnets, or combinations thereof.

The fluid flow paths may be counter flow, co-current flow, cross flow,or combinations thereof.

The one or more plates may comprise dimples or grooves. The dimples orgrooves may comprise spacers that limit movement of the one or moreplates.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the described devices, systems, andmethods will be readily understood, a more particular description of thedevices, systems, and methods briefly described above will be renderedby reference to specific embodiments illustrated in the appendeddrawings. Understanding that these drawings depict only typicalembodiments of the described devices, systems, and methods and are nottherefore to be considered limiting of its scope, the devices, systems,and methods will be described and explained with additional specificityand detail through use of the accompanying drawings, in which:

FIG. 1 shows a cutaway, front-side isometric view of a heat exchanger.

FIG. 2A shows an isometric front-side view of a heat exchanger.

FIG. 2B shows an isometric front-side view of the heat exchanger of FIG.2A with a portion of the outer walls removed.

FIG. 2C shows a cross-sectional front-side view of 202 of FIG. 2B.

FIG. 2D shows an isometric back-side view of the heat exchanger of FIG.2A with a portion of the outer walls removed.

FIG. 2E shows a cross-sectional back-side view of 204 of FIG. 2D.

FIG. 3 shows a method for operating a heat exchanger.

DETAILED DESCRIPTION

It will be readily understood that the components of the presentdevices, systems, and methods, as generally described and illustrated inthe Figures herein, could be arranged and designed in a wide variety ofdifferent configurations. Thus, the following more detailed descriptionof the embodiments of the present devices, systems, and methods, asrepresented in the Figures, is not intended to limit the scope of theinvention, as claimed, but is merely representative of certain examplesof presently contemplated embodiments in accordance with the describeddevices, systems, and methods.

Cryogenic heat exchangers operate at temperatures low enough thatnormally benign gases desublimate, condense, freeze, deposit, orcombinations thereof out of fluids onto surfaces in a solid form, termedfoulant. Foulant builds up on the various surfaces in the heatexchanger, but most especially on heat transfer surfaces. This causesincreased pressure drops across the heat exchanger, increasing operatingexpenses for the heat exchanger while also decreasing heat exchangeefficiency. Various solutions have been attempted, most occurring aftershutdown.

The devices, systems and methods herein prevent or remove foulant duringoperations. The change in pressure caused by foulant deposition is usedto solve the foulant deposition. Rather than brazing plates into thetypical rigid form of traditional plate and frame heat exchangers, thedevices, systems, and methods described herein are designed to allow theplates to move or float depending on the changes in pressure of thefluids or other applied mechanical forces. As foulant deposits withinthe process side of the heat exchanger, pressures in the process flowpath increase. The pressure differential thus formed versus the coolantflow path across the plates pushes outward on the plate, constrictingthe flow of the coolant, increasing the back-pressure on the coolantflow path until the pressures equalize. The movement of the platesbreaks up the solids that have built up in one or more ways. First, themovement itself can cause fracturing of foulant, allowing it to bestripped off the plates. Second, the coolant now has less volume to movethrough, but the same incoming flow. The increased flow velocity throughthe coolant flow path means cooling of the process side decreases, andso the foulant will be warmed by the process fluid, melting,desublimating, or dissolving into the process fluid.

These “floating” plates also provide control benefits for operation ofthe heat exchanger. Controlling the pressure of one fluid can controlthe pressure of both fluids. Dropping fluid flow into the coolant flowpath drops pressure in the coolant flow path such that the plates moveto increase the volume of the process flow path until pressures areequalized.

The floating plate also allows for a pressure impulse to be sent througheither fluid to abruptly move the plates and break up any foulant beforethe foulant causes a sizable pressure drop and a loss of efficiency.

Referring now to the Figures, FIG. 1 shows a cutaway, front-sideisometric view 100 of a heat exchanger 102 that may be used in thedescribed devices, systems, and methods. Heat exchanger 102 comprisesparallel plates 106 and walls 104. Parallel plates 106 comprise ridges108, channels 110, coolant plenum 114, and process plenum 116. Walls 104comprise guides 112. Process fluid 130 passes through process plenum 116and is cooled by coolant 132 which passes through coolant plenum 114.Guides 112, perpendicular to plates 106, allow plates 106 to move withina limited range 118. Ridges 108 contact the underside of channels 110and act as movement limiters. Movement 118 through guides 112 is causedby a pressure differential. The offset of ridges 108 and channels 110prevents the complete closing of plenums 114 and 116. Guides 112 alsolimit the maximum movement of plates 106. Guides 112 prevent torsion ofplates 106 to prevent leakage between plenums 114 and 116. In otherembodiments, movement 118 is caused by an external force.

In one exemplary embodiment, process fluid 130 is pentane with dissolvedcarbon dioxide. Coolant 132 is liquid methane. As the pentane is cooledacross plates 106, a portion of the dissolved carbon dioxidedesublimates out of solution and forms solid carbon dioxide on thesurface of plates 106. This carbon dioxide restricts flow of pentanethrough process plenum 116, resulting in an increase in pressure inprocess plenum 116. As the pressure in process plenum 116 exceeds thepressure in coolant plenum 114, plates 106 begin moving 118 such thatprocess plenum 116 gains volume and coolant plenum 114 loses volume.This movement may remove a portion of the solid carbon dioxide from thesurface due to fracturing of the solid carbon dioxide. Restriction ofthe liquid methane into coolant plenum 114 results in less coolingacross plates 106, such that the pentane doesn't become as cold, and cansublimate, melt, and dissolve the solid carbon dioxide back intosolution.

Referring to FIG. 2A, FIG. 2A shows an isometric front-side view 200 ofa heat exchanger 206 that may be used in the described devices, systems,and methods. FIG. 2B shows an isometric front-side view of the heatexchanger 206 of FIG. 2A with a portion of the outer walls removed. FIG.2C shows a cross-sectional front-side view of heat exchanger 206 of FIG.2B. FIG. 2D shows an isometric back-side view of the heat exchanger 206of FIG. 2B. FIG. 2E shows a cross-sectional back-side view of 204 ofFIG. 2D.

The heat exchanger 206 comprises shell 208, process inlet pipe 232,process outlet pipe 234, coolant inlet/outlet pipe 236, coolant internalpipe 238, and plates 214. Shell 208 comprises box 242, head plate 212,and tail plate 210. Head plate 212 and tail plate 210 are fixed inplace. Coolant inlet/outlet pipe 236 comprises coolant inlet 218,coolant outlet 222, slits 244 and 246, separators 252, and spacers 240.Coolant internal pipe 238 comprises slits 248 and 250, separators 252,and spacers 240. Process inlet pipe 232 comprises process inlet 216,spacers 240, slits 258 and 260, separators 252. Process outlet pipe 234comprises process outlet 220, spacers 254 and 256, slits 236, andseparators 252. The plenums between plates 214 and between plates 214head and tail plates 212/210 alternate as ascending-coolant plenum 224,descending-process plenums 228, descending-coolant plenum 226,ascending-process plenum 230, and then repeats the pattern.

Process fluid 270 enters process inlet 216 and is forced by a separator252 to pass through a first slit 258 into the first descending-processplenum 228. Process fluid 270 then passes through a first slit 254 intoprocess outlet pipe 234 and is forced by a separator 252 to pass throughthe next slit 256 into ascending-process plenum 230. Process fluid 270reenters process inlet pipe 232 through a slit 260. This pattern repeatsuntil process fluid 270 passes out process outlet 220.

Coolant 280 enters coolant inlet 218 and is forced by a first separator252 to pass through a slit 244 into the first ascending-coolant plenum224. Coolant 280 then passes through a slit 250 into coolant internalpipe 238, and is forced by a separator 252 to pass through the next slit248 into descending process plenum 226. Coolant 280 then passes througha slit 246, reentering coolant inlet/outlet pipe 236. This patternrepeats until Coolant 280 passes out coolant outlet 222.

Plates 214 conduct heat between process fluid 270 and coolant 280.Plates 214 can move perpendicular to the plane of the plates. Pipes 232,234, 236, and 238 serve as guides for plates 214, limiting the movementof the plate to the perpendicular. They are also a path for fluid flow,a mount for spacers, and as a structural support of the heat exchanger.Pipes 232, 234, and 238 are mounted to head or tail plate 212/210 forrigidity and structural support where pipes 232, 234, and 238 do notpass through both head and tail plate 212/210. This mounting is notshown for clarity of drawings.

Plates 214 can move side to side between spacers 240 due to pressuredifferences between coolant and process plenums. The spacers 240 limitthe maximum travel distance of plates 214. Spacers 240 also keep plenums224, 226, 228 and 230 aligned with their corresponding slits. By placingthe spacers where they are, the openings 230 and 232 are locked to thecorrect plenum. This arrangement allows the fluid to flow throughplenums 224, 226, 228, and 230 without backflow or mixing of processfluid 270 with coolant 280.

Referring to FIG. 3, FIG. 3 shows a method 300 for operating a heatexchanger that may be used in the described devices, systems, andmethods. A first fluid is received in a first plenum defined by a spacebetween a first plate and a second plate of the heat exchanger 301. Asecond fluid is received in a second plenum defined by a space outsidethe first plate, the second plate, or both 302. The first plate, thesecond plate, or both move along guides based on changes in pressure inthe first plenum or the second plenum; application of an external forceto the first plate, the second plate, or both; or a combination thereof303.

In some embodiments, the spacers are mounted on the guides. In someembodiments, the spacers are mounted on the one or more plates. In someembodiments, the spacers limit the movement of the one or more platessuch that the fluid plenums aligned with each of the plurality of fluidinlets and each of the plurality of fluid outlets do not change.

In some embodiments, the one or more plates are sufficiently rigid thatthe one or more plates move when an even force is applied to the plate.

In some embodiments, the one or more plates comprise silicone, aluminum,steel, copper, bronze, plastic, or combinations thereof.

In some embodiments, the one or more plates flex such that solids thatdeposit on the one or more plates are broken off. In some embodiments,the one or more plates are pre-tensioned to buckle when a pressuredifferential between sides of the one or more plates exceeds a limit. Insome embodiments, the one or more plates flex such that solids thatdeposit on the one or more plates are broken off.

In some embodiments, the one or more plates are prevented from movingwhen a temperature limit is reached by a mechanical locking mechanism,temperature-induced expansion or contraction of the one or more plates,temperature-induced expansion or contraction of the chamber, orcombinations thereof.

In some embodiments, the one or more plates comprise an electroactivematerial that flexes or deforms when a charge is applied to the one ormore plates.

In some embodiments, the heat exchanger comprises one or more pressuresensors, one or more temperature sensors, or a combination thereof.

In some embodiments, the one or more plates are vibrated to break offsolids deposited on the one or more plates.

In some embodiments, the external force applied to the one or moreplates is provided by a piston, gears, electromagnets, or combinationsthereof.

In some embodiments, the fluid flow paths are counter flow, co-currentflow, cross flow, or combinations thereof.

In some embodiments, the one or more plates comprise dimples or grooves.In some embodiments, the dimples or grooves comprise spacers that limitmovement of the one or more plates.

1. A heat exchanger comprising: a chamber comprising a plurality offluid inlets and a plurality of fluid outlets; and one or more platesinside the chamber, the one or more plates being parallel and definingfluid plenums between each of the one or more plates, the fluid plenumsdefining a fluid flow path, wherein each of the fluid plenums compriseone of the plurality of fluid inlets, one of the plurality of fluidoutlets, a fluid path between at least two of the fluid plenums, or acombination thereof, wherein the one or more plates being movablymounted between guides perpendicular to a plane of the one or moreplates, and wherein the one or more plates move along the guides,wherein the one or more plates move along the guides due to changes inpressure in the fluid plenums, application of an external force to theone or more plates, or a combination thereof.
 2. The heat exchanger ofclaim 1, further comprising spacers that limit movement of the one ormore plates.
 3. The heat exchanger of claim 2, wherein the spacers limitthe movement of the one or more plates such that the fluid plenumsaligned with each of the plurality of fluid inlets and each of theplurality of fluid outlets do not change.
 4. The heat exchanger of claim1, wherein the one or more plates are sufficiently rigid that the one ormore plates move when an even force is applied to the plate.
 5. The heatexchanger of claim 1, wherein the one or more plates comprise silicone,aluminum, steel, copper, bronze, plastic, or combinations thereof. 6.The heat exchanger of claim 5, wherein the one or more plates flex suchthat solids deposited on the one or more plates break off.
 7. The heatexchanger of claim 1, wherein the one or more plates comprise anelectroactive material that flexes or deforms when a charge is appliedto the one or more plates.
 8. The heat exchanger of claim 1, furthercomprising one or more pressure sensors, one or more temperaturesensors, or a combination thereof.
 9. The heat exchanger of claim 1,wherein the one or more plates comprise dimples or grooves.
 10. The heatexchanger of claim 9, wherein the dimples or grooves comprise spacersthat limit movement of the one or more plates.
 11. A method foroperating a heat exchanger comprising: receiving a first fluid in afirst plenum defined by a space between a first plate and a second plateof the heat exchanger; receiving a second fluid in a second plenumdefined by a space outside the first plate, the second plate, or both;moving the first plate, the second plate, or both, along guides basedon: changes in pressure in the first plenum or the second plenum;application of an external force to the first plate, the second plate,or both; or, a combination thereof.
 12. The method of claim 11, whereinthe heat exchanger further comprises spacers that limit movement of thefirst plate, the second plate, or both the first plate and the secondplate.
 13. The method of claim 12, limiting the movement of the firstplate, the second plate, or both the first plate and the second plate bymeans of spacers or an external force such that the fluid plenumsaligned with each of the plurality of fluid inlets and each of theplurality of fluid outlets do not change.
 14. The method of claim 11,wherein the first plate, the second plate, or both the first plate andthe second plate are sufficiently rigid that the first plate, the secondplate, or both the first plate and the second plate moves when an evenforce is applied to the plate.
 15. The method of claim 11, wherein thefirst plate, the second plate, or both the first plate and the secondplate comprise silicone, aluminum, steel, copper, bronze, plastic, orcombinations thereof.
 16. The method of claim 15, flexing the firstplate, the second plate, or both the first plate and the second platesuch that solids deposited on the one or more plates break off.
 17. Themethod of claim 11, wherein the first plate, the second plate, or boththe first plate and the second plate comprise an electroactive materialthat flexes or deforms when a charge is applied to the one or moreplates.
 18. The method of claim 11, the heat exchanger furthercomprising one or more pressure sensors, one or more temperaturesensors, or a combination thereof.
 19. The method of claim 11, whereinthe first plate, the second plate, or both the first plate and thesecond plate comprise dimples or grooves.
 20. The method of claim 19,limiting movement of the first plate, the second plate, or both thefirst plate and the second plate by the dimples or grooves acting asspacers.